The reason is that the sun's 'hot zone' will expand... Photo-581346.70756 - seattlepi.com

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In 1.75 billion to 3.25 billion years Earth will be in the hot zone, "with temperatures so high that the seas would evaporate," lead author Andrew Rushby said in a news release. "We would see a catastrophic and terminal extinction event for all life." less

In 1.75 billion to 3.25 billion years Earth will be in the hot zone, "with temperatures so high that the seas would evaporate," lead author Andrew Rushby said in a news release. "We would see a catastrophic and ... more

Photo: Alexander Zemlianichenko, AP

In 1.75 billion to 3.25 billion years Earth will be in the hot... Photo-1915372.70756 - seattlepi.com

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“Of course conditions for humans and other complex life will become impossible much sooner," Rushby said. "Humans would be in trouble with even a small increase in temperature."

“Of course conditions for humans and other complex life will become impossible much sooner," Rushby said. "Humans would be in trouble with even a small increase in temperature."

Photo: Matt York, STF

“Of course conditions for humans and other complex life will... Photo-4852551.70756 - seattlepi.com

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"Near the end only microbes in niche environments would be able to endure the heat."

"Near the end only microbes in niche environments would be able to endure the heat."

Photo: Bob Andersen & D. J. Patterson

"Near the end only microbes in niche environments would be... Photo-2416623.70756 - seattlepi.com

Of course, climate change is just one of the ways we could do ourselves in much sooner. There's also the bomb ...

Of course, climate change is just one of the ways we could do ourselves in much sooner. There's also the bomb ...

Of course, climate change is just one of the ways we could do... Photo-2518159.70756 - seattlepi.com

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And the potential for science gone awry.

And the potential for science gone awry.

Photo: WETA Digital, 20th Century Fox

And the potential for science gone awry. Photo-4934667.70756 - seattlepi.com

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Or an asteroid could slam into Earth.

Or an asteroid could slam into Earth.

Photo: Uncredited, Associated Press

Or an asteroid could slam into Earth. Photo-4202993.70756 - seattlepi.com

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After all, there are more than 1,400 "Potentially Hazardous Asteroids" -- at least 460 feet across and in orbits that pass close to Earth's orbit.

After all, there are more than 1,400 "Potentially Hazardous Asteroids" -- at least 460 feet across and in orbits that pass close to Earth's orbit.

After all, there are more than 1,400 "Potentially Hazardous... Photo-5006987.70756 - seattlepi.com

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A gamma ray burst could take us out from afar. This burst 12 billion light years away released almost as much energy in one second as all of the stars in the universe, according to astronomers.

A gamma ray burst could take us out from afar. This burst 12 billion light years away released almost as much energy in one second as all of the stars in the universe, according to astronomers.

A gamma ray burst could take us out from afar. This burst 12... Photo-2271496.70756 - seattlepi.com

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What's the point of all this?

"Looking at habitability metrics is
useful because it allows us to investigate the potential for other
planets to host life, and understand the stage that life may be at
elsewhere in the galaxy," Rushby said. “Of course, much of evolution is
down to luck, so this isn’t concrete, but we know that complex,
intelligent species like humans could not emerge after only a few
million years because it took us 75 per cent of the entire habitable
lifetime of this planet to evolve. We think it will probably be a
similar story elsewhere." less

What's the point of all this?

"Looking at habitability metrics is useful because it allows us to investigate the potential for other planets to host life, and understand the stage that life may be at ... more

Photo: ESO, AFP/Getty Images

What's the point of all this? "Looking at habitability... Photo-2296292.70756 - seattlepi.com

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So what are we to do once Earth gets too hot?

"(I)t is possible that there will be a habitable, Earth-like planet within 10 light-years, which is very close in astronomical terms," Rushby said. "However reaching it would take hundreds of thousands of years with our current technology." less

So what are we to do once Earth gets too hot?

"(I)t is possible that there will be a habitable, Earth-like planet within 10 light-years, which is very close in astronomical terms," Rushby said. "However reaching ... more

Photo: AP

So what are we to do once Earth gets too hot? "(I)t is... Photo-1994650.70756 - seattlepi.com

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"If we ever needed to move to another planet, Mars is probably our best bet. It’s very close and will remain in the habitable zone until the end of the Sun’s lifetime - six billion years from now."

Whew.

"If we ever needed to move to another planet, Mars is probably our best bet. It’s very close and will remain in the habitable zone until the end of the Sun’s lifetime - six billion years from now."

Whew.

Photo: Associated Press

"If we ever needed to move to another planet, Mars is probably... Photo-3293033.70756 - seattlepi.com